Dynamoelectric machine



p 28, 1965 G. E. BOLLIBON ETAL. 3,209,183

DYNAMOELECTRIC MACHINE Original Filed July 10, 1958 United States Patent3,209,183 DYNAMOELECTRIC MACHINE George E. Bollibon, Pittsburgh, andEdward A. Macha, Wilmerding, Pa., assignors to Westinghouse ElectricCorporation, East Pittsburgh, Pa., a corporation of PennsylvaniaOriginal application July 10, 1958, Ser. No. 747,771, now Patent No.3,013,500, dated Dec. 19, 1961. Divided and this application Mar. 1,1961, Ser. No. 92,539

The present invention relates to dynamoelectric machinery and moreparticularly to a new and improved construction of a motor-pump unitadapted for pumping fluids at elevated temperatures in which thebearings of the pump are lubricated by the fluid being pumped. Thisapplication is a division of copending application Serial No. 747,771,filed July 10, 1958 and entitled Sealed Dynanoelectric Machine, nowPatent 3,013,500, issued December 19, 1961.

Motor-pump units of the character described frequently are employed insealed applications. Such units employ a sealed stator cartridge and asealed rotor bore with the rotor bore being separated from the statorcartridge by an enclosure or can. It is desirable to provide for accessto the rotor Without dismantling the stator cartridge, and likewise, toobtain access to the stator without disturbing the rotor.

It is also desirable to provide means for relatively easy removal of thestator assembly from the motor-pump unit for purposes of repair orreplacement. Such removal is facilitated by the invention, particularlywhere the stator assembly is hermetically sealed, by furnishing thestator assembly and component structural parts in the form of aremovable cartridge. The stator cartridge is arranged for ready removalfrom the motor housing after first disengaging the latter. Similarlyaccess to the rotor bore is facilitated by the invention through the useof access openings and removable bearing mountings.

It is therefore an object of the invention to provide a novel andefiicient motor-pump unit adapted particularly for pumping fluids atelevated temperatures.

Another object of the invention is the provision of the motor-pump unithaving improved means for mounting the rotor bearings to afford accessto the rotor without disturbing the stator.

Still another object of the invention is to provide a motor-pump unithaving improved means for facilitating removal of and for cooling thestator assembly.

Another object of the invention is the provision of a dynamoelectricmachine having an improved cartridge type stator, whereby the stator isadapted for easy removal.

During the course of the following detailed description of an exemplaryform of the invention, the foregoing and additional objects, featuresand advantages of the invention will be elaborated upon. The followingdescription is to be read in conjunction with the accompanying drawings,in which:

The figure is an elevational view partially in section of one form ofthe invention as arranged for application With a motor-pump unit.

With reference now more particularly to the drawings, the illustrativeform of the invention shown therein is associated with a motor-pump unit20 including a motor housing 22 and a pump casing 24. A driving shaft 26is mounted for rotation within the motor housing 22 on a pair of radialbearing arrangements 28 and 30 presently to be described. A rotor 32 issecured to the driving shaft 26 for rotation therewith at a positionintermediate the bearings 28 and 30. The lower end of the driving shaftas viewed in the figure of the drawings extends downwardly into the pumpcasing 24, to which end a 3,289,183 Patented Sept. 28, 1965 pumpimpeller 34 is secured for rotation within the pump casing 24. i

The interior of the pump casing 24 is formed into a spiral dischargepassage 36, termed a volute, and an intake or suction port 42 whichcommunicates with eye 44 of the impeller 34. A labyrinth seal ofconventional design, which is denoted generally by the referencecharacter 46, is mounted in the pump casing 24 at a position adjacentthe eye 44 of the impeller to prevent high pressure fluid in the volute36 from flowing back to the intake port 42. The impeller 34 is providedwith a plurality of vanes or blades 48 in a conventional manner, whichpropel fluid from the intake port 42 into the volute 36.

The rotor 32 is positioned within a generally tubular stator cartridge50. The stator cartridge 50 includes a hollow stator core 52 providedwith windings in the well known manner, the end turns of which aredesignated by the reference characters 54 and 56. The end turns 54 and56 in this example extend through slotted end rings 58 and 60 and areembedded in a conventional potting compound 62. The stator 52 is encasedwithin an outer shell 64 which is joined at its ends as by welding to apair of annular end rings or tubular extensions 66 and 68.

At each end of the stator core 52 adjacent the bore 70 thereof, aback-up and spacing sleeve 72 or 74 is mounted in alignment with thebore 70 and engages the tubular extensions 66 and 68 respectively. Theoutward ends of the sleeves 72 and 74 are desirably seated respectivelyin offset portions 76 formed at the inner periphery of the end members66 and 68.

The stator 52 is hermetically sealed within the cartridge 50 by means ofa stator can or enclosure 80. The stator can 80 desirably is fabricatedfrom a corrosion-resistant material, such as stainless steel, in orderto ensure its integrity. The enclosure is hermetically sealed at itsends to the end members 66 and 68 respectively by means of annularsealing welds at 82 and 84.

Terminal means such as terminal 71 for the stator 52 extendslongitudinally through suitable apertures in the upper end member 66 forconnection to the stator windings. The outward end of the terminal 71 ishoused within a removable connection box 73.

The cartridge shell 64 fits relatively closely within the motor housing22 and the upper end member 66 of the stator cartridge 50 is retainableby engagement between its annular shoulder 86 and an integral lip 88formed at the upper end of the motor housing 22. In practice however, agap 90 is left between the end member shoulder 86 and the housing lip 88to compensate for manufacturing clearances and for differentiallongitudinal expansion between the cartridge shell 64 and the adjacenthousing 22. The stator cartridge 50 therefore actually is positionedwithin the motor housing 22 by engagement of the lower end member 68,provided with a stepped configuration for this purpose, with mountingflange 92 at the lower end of the housing 22 and by additional meanspresently to be described. When operating the pump with a pressurizedfluid, the fluid within the rotor cavity 70, of course, exerts apressure radially to the stator cartridge 50 and therefore nolongitudinal force is imparted to the upper end member 66.

To aid in assembling the motor-pump unit 20, the lower end member 68 ofthe stator cartridge is secured initially to the lower end 92 of thehousing 22 by means of a plurality of bolts 93. Engagement between thelower end member 68 and the housing flange 92 is maintained afterassembly of the motor-pump unit 20 by a plurality of main flange ormounting studs 95 and associated components presently to be described.However, in the event of rupture in the stator can 80, the systempressure, of course, would be applied to the interior of the statorcartridge in which case the upper end member 66 would be forced againstthe retaining lip 88 of the housing 22.

The radial bearings 28 and 30, which are employed as aforesaid formounting the driving shaft, are supported respectively by the stator endmembers 66 and 68. The bearing assemblies 28 and 30 each comprise abearing cartridge 94 of known design which is arranged for bearingengagement with a shaft sleeve or journal member 96.

Each bearing 28 and 30 is provided with a mounting member 98 and themounting members 98 are retained within the cartridge end members 66 and68 respectively by engagement between the ends of the stator enclosure80 and by a pair of retaining rings 112 and 114, as shown in the figure.The retaining rings 112 and 114 are seated into circumferential groovesprovided in the end members 66' and 68 adjacent the outward ends of thebearing mounting members 98.

When disassembling the motor-pump unit 20 to remove the bearings 28 and30, it is only necessary to disengage the retaining rings 112 and 114.The lower retaining ring 114, of course, is accessible by disengagingthe mounting studs 95 and raising the motor housing 22 and statorcartridge 50 secured thereto a short distance and inserting a suitabletool to remove the retaining ring 114. Following this operation, thestator 52 and the housing 22 can be lifted from the rotor 32 andassociated components.

The upper bearing assembly 28 is accessible without disassembling themotor-pump unit by removing stator cartridge cap 116. The cap 116 isprovided with a reduced portion 118 whereby the cap 116 is inserted intothe open end of the upper stator cartridge end member 66 and secured inthis position by means of a plurality of mounting bolts 120. Thejunction between the stator cartridge 50 and its cap 116 is sealed bymeans of a sealing ring 122 inserted into an annular groove 124 formedin one of the confronting surfaces of the cap 116 and the statorcartridge 50. In this arrangement the groove 124 and ring 122 areapplied to the reduced portion 118 of the stator cartridge cap. Withthis arrangement the rotor cavity '70 is sealed within the statorcartridge 50.

The rotor cavity 70 is prevented from communicating with the interior ofthe pump casing or volute 36 by means of the lower radial bearing 30, athermal barrier 126, and labyrinth seals 128 and 130.

A thrust runner 132 is secured to the driving shaft 26 for rotationtherewith and is provided with an annular bearing member 134. Thebearing member 134 is arranged for engagement with a Kingsbury typethrust bearing denoted generally by the reference numeral 136 or with athrust bearing and thermal barrier arrangement of the type described andclaimed in a copending application of G. E. Bollibon et al., entitledMotor-Pump Unit, filed September 3, 1958, Serial No. 758,809, and nowPatent 2,972,309, assigned to the assignee of the present application.

Although the cartridge shell 64 is furnished initially with suitableclearances to enable facile insertion of the stator cartridge 50 intothe motor housing 52, the cartridge shell 64 will expand at the normaloperating temperatures of the operating pump unit into continguousengagement with the inner periphery of the motor housing 22 with theresult that the rate of heat transfer between the cartridge shell 64 andthe housing 22 is increased greatly. This expansion of the cartridge 64relative to the motor housing 22 occurs on at least two accounts:Firstly, the cartridge shell 64 being adjacent the stator 52 is atslightly higher temperature. In the second place, the motor housing 22is considerably thicker in the radial direction than is the cartridgeshell 64 and therefore the radial expansion of the housing is less. Inaddition, the enclosure 80 being closer to the rotor bore 70 andadjacent stator 50 and being thinner than both shell 64 and housing 22will also be subjected to different thermal conditions,

4 resulting both in different thermal expansion coefficients and fasterthermal expansion rates than housing 22.

For additional information concerning the description and operation ofother features of the canned motor pump which do not pertainspecifically to the inventive features in this divisional application,reference may be had to the parent application, now Patent 3,013,500,issued December 19, 1961 which is incorporated by reference herein.

From the foregoing description it will be apparent that a novel andefiicient motor-pump unit has been disclosed herein. It will beunderstood that the accompanying descriptive materials are presented forpurposes of exemplifying the invention and should not be interpreted aslimitative thereof.

Numerous embodiments therefore will occur to those skilled in the artwithout departing from the spirit and scope of the invention. Moreover,it is to be understood that certain features of the invention can beemployed without a corresponding use of other features.

We claim as our invention:

1. A dynamoelectric machine comprising a tubular housing; a tubularstator cartridge inserted within said housing and conforming thereto,said cartridge including a shell, a stator core, a pair of sleevesspaced from said shell and engaging respectively the ends of said core,a pair of end rings engaging respectively the ends of said shell and theadjacent ends of said sleeves for enclosing said cartridge; a drivingshaft mounted within said stator cartridge; anti-frictional meansmounted on said stator cartridge and supporting said shaft for rotation;a rotor secured to said driving shaft for rotation therewith, said rotorbeing disposed within said stator core; an outwardly extending flangeformed on one of said end rings and overlying the adjacent end of saidhousing; means for mounting said flange in engagement with said adjacenthousing end; and a pair of cooperating stops secured respectively to theopposite end of said housing and the other of said end rings, said stopsbeing disposed in juxtaposed relation to retain said stator cartridgewithin said housing but being spaced to permit longitudinal expansion ofsaid cartridge relative to said housing prior to engagement of saidstops; and means for closing the open ends of said stator cartridge.

2. A dynamoelectric machine comprising a relatively thick tubularouterhousing capable of retaining a pressurized high temperature fluidtherein; a stator cartridge inserted within said housing, said statorcartridge including an outer shell conforming substantially to said housing, a hollow stator assembly inserted within said shell, a pair ofsleeve members spaced from said shell and engaging the ends of saidstator assembly at the inner periphery thereof, and means for enclosingthe space between the ends of said shell and the outward endsrespectively of said sleeves; a driving shaft mounted within said statorcartridge; anti-frictional means mounted on said enclosing means andsupporting said shaft for rotation; a rotor secured to said drivingshaft for rotation therewith, said rotor being disposed within saidstator core; means for closing and sealing the open ends of said statorassembly; heat transfer means for removing heat from the outer surfaceof said housing; and said outer shell being relatively thinner than saidhousing, whereby the heat and pressure of the interior of saiddynamoelectric machine causes said shell to expand into contiguouscontact with said housing.

3. A stator cartridge for a dynamoelectric machine, said cartridgeincluding a stator assembly of annular configuration, a pair ofrelatively thick end rings spaced from the ends of said stator assembly,respectively, supporting means disposed adjacent the inner periphery ofsaid assembly and said end rings and fixedly secured to the latter, anouter casing for said cartridge of annular configuration, said outercasing being mounted on said cartridge and receiving said statorassembly and at least a portion of each of said end rings therein, oneof said end rings including an outwardly extending flange memberdisposed in the outer periphery thereof and extending toward saidcasing, said casing having a circumferential projection disposedadjacent one end thereof and extending inwardly from the inner peripherythereof to overlie said flange, said projection being axially spacedfrom said flange to form an axial clearance therebetween and beingdisposed between said flange and the outwardly facing end surface ofsaid one end ring, whereby said flange must be moved axially to engagesaid projection and means coupled to the other end of said casing forfixedly securing said casing in the aforesaid position.

4. In a dynamoelectric machine, a stator cartridge of annularconfiguration, a rotor disposed within said cartridge and mounted forrotation therewithin, said cartridge including a stator assembly ofannular configuration, a pair of relatively thick end rings spaced fromthe ends of said stator assembly, respectively, supporting meansdisposed adjacent the inner periphery of said assembly and said endrings and fixedly secured to the latter, an outer casing for saidcartridge of annular configuration, said outer casing being mounted onsaid cartridge and receiving said stator assembly and at least a portionof each of said end rings therein, one of said end rings including anoutwardly extending flange member disposed on the outer peripherythereof and extending toward said casing, said casing having acircumferential projection disposed adjacent one end thereof andextending inwardly from the inner periphery thereof to overlie saidflange, said projection being axially spaced from said flange to form anaxial clearance therebetween and being disposed between said flange andthe outwardly facing end surface of said one end ring, whereby saidflange must be moved axially to engage said projection, and meanscoupled to the other end of said casing for fixedly securing said casingin the aforesaid position.

5. A dynamoelectric machine comprising, a tubular stator cartridge, arelatively thick tubular outer housing receiving said stator cartridgethereon, a pair of tubular extensions positioned in alignment with andspaced from the ends of said stator cartridge, the openings in saidtubular stator cartridge and in said tubular extensions being aligned toform a rotor bore, relatively thin tubular enclosure means extendingalong said rotor bore and secured respectively at its ends to saidtubular extensions to isolate said rotor bore from said statorcartridge, means for closing the ends of said rotor bore, said outerhousing having one end thereof fixedly positioned relative to one ofsaid extensions, said other housing end and said other extension havingaxially spaced cooperative stop means thereon positioned to form anaxial clearance therebetween to permit limited axial movement of saidother extension relative to said housing.

References Cited by the Examiner UNITED STATES PATENTS 2,654,848 10/53Schaefer 310-87 X 2,687,695 8/54 Blom 310-86 X 2,739,252 3/56 Pattersonet al. 310-87 2,761,985 9/56 Schaefer 310-87 2,777,963 1/57 Kuntz 310-86X 2,883,566 4/59 Briggs 310-87 2,887,061 5/59 Cametti et al 310-87X2,887,062 5 59 Cametti 310-54 2,913,988 11/59 White 310-54 2,944,2977/60 Maynard 310-87 X 2,964,659 12/60 Steele 310-54 3,067,690 12/ 62Kramer 310-86 MILTON O. HIRSHFIELD, Primary Examiner.

3. A STATOR CARTRIDGE FOR A DYNAMOELECTRIC MACHINE, SAID CARTRIDGEINCLUDING A STATOR ASSEMBLY OF ANNULAR CONFIGURATION, A PAIR OFRELATIVELY THICK END RINGS SPACED FROM THE ENDS OF SAID STATOR ASSEMBLY,RESPECTIVELY, SUPPORTING MEANS DISPOSED ADJACENT THE INNER PERIPHERY OFSAID ASSEMBLY AND SAID END RINGS AND FIXEDLY SECURED TO THE LATTER, ANOUTER CASING FOR SAID CARTRIDGE OF ANNULAR CONFIGURATION, SAID OUTERCASING BEING MOUNTED ON SAID CARTRIDGE AND RECEIVING SAID STATORASSEMBLY AND AT LEAST A PORTION OF EACH OF SAID END RINGS THEREIN, ONEOF SAID END RINGS INCLUDING AN OUTWARDLY EXTENDING FLANGE MEMBERDISPOSED IN THE OUTER PERIPHERY THEREOF AND EXTENDING TOWARD SAIDCASING, SAID CASING HAVING A CIRCUMFERENTIAL PROJECTION DISPOSEDADJACENT ONE END THEREOF AND EXTENDING INWARDLY FROM THE INNER PERIPHERYTHEREOF TO OVER LIE SAID FLANGE, SAID PROJECTION BEING AXIALLY SPACEDFROM SAID FLANGE TO FORM AN AXIAL CLEARANCE THEREBETWEEN AND BEINGDISPOSED BETWEEN SAID FLANGE AND THE OUTWARDLY FACING END SURFACE OFSAID ONE END RING, WHEREBY SAID FLANGE MUST BE MOVED AXIALLY TO ENGAGESAID PROJECTION AND MEANS COUPLED TO THE OTHER END OF SAID CASING FORFIXEDLY SECURING SAID CASING IN THE AFORESAID POSITION.